Chronic Intestinal pseudoobstruction
Intestinal pseudoobstruction is characterized by symptoms of intestinal intestine obstruction in the absence of a mechanical obstruction. The mechanisms for controlling orderly propulsive motility fail while the intestinal lumen is free form obstruction. This syndrome may result from abnormalities of the muscles of ENS. In general symptoms of colicky abdominal pain, nausea and vomiting, and abdominal distension simulate mechanical obstruction.Pseudoobstruction may be associated with degenerative changes is the ENS. Failure of propulsive motility reflects the loss of the neural networks that program and control the organized motility patterns of the intestine. This disorder can occur in varying lengths of intestine of in the entire length of the small intestine. Contractile behavior of the of the circular muscle is hyperactive but disorganized in the denervated segments. The behavior reflects the absence of inhibitory nervous control of the muscles, which are self-excitable when, released form the braking action of enteric inhibitory neurons.
Another form of pseudoobstruction is paralytic ileus characterized by prolonged motor inhibition .The electrical slow waves are normal but muscular action potentials and contractions are absent. Prolonged ileus commonly occurs after abdominal surgery. The illus. results form suppression of the synaptic circuits that organize propulsive motility in the intestine. A probable mechanism is presynaptic inhibition and the closure of the synaptic gates.Continuous discharge of the inhibitory motor neurons accompanies suppression of the motor circuits. This activity of the inhibitory motor neurons prevents the circular muscle form responding to electrical slow waves, which are undisturbed in ileus.
References:
- Short practice of surgery, bailey and love, 25th edi.
- Harrison’s Principles of Internal Medicine, 17th edition.
- Davidson’s Principles and Practice of Medicine, 20th Edition
- The Washington Manual of surgery, 5th edition.
- Medical physiology, Lippincott Williams & Wilkins 3rd edi.
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